The mechanism by which lung interstitial edema fluid and edema fluid in the airspace is cleared during the resolution of acute pulmonary edema will be studied in dogs after rapid infusion of 0.9% NaCl to 15 to 30% of body weight. Preliminary experiments support the hypothesis that lung lymph flow rate an composition change as a function of pulmonary microvascular pressure in hypervolemic dogs and that the lymphatic drainage systemic does not play a quantitatively important role in the clearance of lung edema fluid. In contrast, the lymphatic drainage system of the abdomen as reflected in thoracic duct lymph seems to function in part to drain peritoneal edema fluid. Histologic studies utilizing the fluorescent properties of Evans Blue albumin will study the appearance time and the distribution of edema fluid in the airspace. These studies will also provide some information on the dynamics of protein flux through the edematous perivascular and peribronchial interstitial space. Finally, we will study the efficacy of pharamacological doses of furosemide or albumin in promoting a more rapid clearance of lung edema fluid.